Color vision-defects are prevalent in the male population. The majority of congenital color deficiencies affect red-green function. Roughly 8% of Caucasian males have a measurable inability to distinguish between red and green--a deficiency called red-green dichromacy. Often, persons having some degree of color blindness, even a significant degree, are not diagnosed unless they are formally tested or accidentally uncover it through some event. This is particularly the case, since many cases of color vision defects are only mild. Nevertheless, even in these cases, the deficiency can have a noticeable effect on the ability of the person to fully distinguish colors.
Color vision tests are employed clinically to identify and differentiate congenital and acquired color vision deficiencies. These tests are primarily designed to identify people with congenital protan (red) or deutan (green) deficiencies which occur in about 8% of the male population and about 0.5% of the female population. Testing for color vision deficiencies is often done using four principal types of tests: pseudiosochromatic plates, anomaloscopes, arrangement tests (hue discrimination) and lanterns.
Printed pseudiosochromatic plates are the most widely used color vision screening tests. These tests are comprised of a pattern of colored dots, chosen and placed so that a person unable to distinguish red, for example, will be unable to discern a number or a letter formed in red against a setting of other colored dots. If a series of pseudiosochromatic plate tests are presented to the user and the answers correlated after the test is administered, various types of color vision defects can be diagnosed.
Another commonly used type of color vision test is an "arrangement test." Arrangement tests require a person to arrange a number of color chips in order of similarity.
Anomaloscopes have been used for color-vision testing since the late 19th century. These devices work by projecting three different monochromatic lights onto a screen. The anomaloscope relies on the fact that people with normal color vision have two classes of color detectors--the red and the green--operating at the red-to-green end of the color spectrum.
Lantern tests are used to test for color naming and are primarily used to discern signal recognition in maritime, military, aviation and transport services.
In an age when more and more educational, commercial and even entertainment activities take place through use of computers utilizing color monitors, color plays an increasingly important role in conveying information and symbolizing attributes or characteristics. For example, in a computer application, a word or symbol may be presented with green-colored text as a "hot" term--to distinguish it from the rest of the text--connoting a link to other information or some other attribute.
The disadvantages caused by an inability to perceive such a "hot" term are increasingly serious. Computer software, including application programs such as graphics programs, word processing programs and spreadsheet programs, and operating systems and environments such as DOS, OS/2 and Windows, often utilize preset--or default--color palettes on the display which include different colored "hot" terms. While these programs generally permit users to alter the color palette for personal reasons in an ad hoc manner, they are not designed to compensate automatically for any color vision deficiencies of the user. A person with abnormal color vision might or might not succeed in choosing display colors that match his best ability to perceive. The software would give him no active guidance in this respect, merely a passive preview facility.
There is an increasing need, therefore, to provide a structured, reliable deliberate and automatic way of adjusting color displays to correct for color vision defects of computer users. Despite this need, there has never been an apparatus or method for integrating a color vision test with the operation of a computer system to automatically optimize the use of color or other symbols in view of the results of the test. While it is known to use a computer to conduct certain vision tests, such as is reported in Computerized Scoring and Graphing of the Farnsworth-MunseH 100-Hue Color Vision Test, Miguel Lugo and James S. Tiederman, American Journal or Ophthalmology 101:469-474, April, 1986, or Computerized Colour Vision Testing, Edsel B. Ing, John A. Parker and Loft-Anne Emerton, Can. J. Ophthalmol--vol 29, no. 3, 1994, there has not been any recognition of the present invention: using the results of the computerized color vision test to alter the setting of the computer display for the benefit of the user.